We at Exquisite Dish have been experimenting a great deal in recent days with an easy and highly customizable recipe for thumbprint cookies, originally posted by the NY Times in December 2013. Readers may also know these cookies, which are essentially a variation of French sablés, as butter cookies or sandies; they are also a very close relative of shortbread. Because they need not be made with eggs nor glutinous flours, they are suitable for a wide variety of special diets.
First we streamlined a few of the Times' techniques and then we tried several different combinations of nuts, jams and gluten-free flours, on occasion toasting and grinding the nuts ourselves, and in other trials using (untoasted) commercially-ground nut meals or flours for simplicity. We had great success with pistachios, vanilla extract, apricot jam and gluten-free oat flour. Hazelnut meal with sorghum flour, almond extract and seedless blackberry jam also made a dainty and delicious cookie. But when we needed a nut-free version to bring to a party, we decided to see just how far we could take the substitutions. Since we could not procure pumpkin seeds or sunflower seeds without a nut disclaimer on a tight deadline, we took another route and used Arrowhead Mills' gluten-free millet flour and brown rice flour along with seedless raspberry jam and rosewater. We decided not to swap out the butter, since it gives these cookies their characteristic richness and crumb, but if necessary, one could even replace butter with a high-quality margarine (such as Earth Balance) and simply omit the added salt. For those who are not fans of jam, a single chocolate chip or small amount of gluten-free ice cream topping, such as the cream caramel sauce produced by Kings Cupboard, would also make excellent fillings.
This recipe makes approximately 30 two-bite cookies. Note: Pictured cookies are made with hazelnut flour and blackberry jam. The millet-brown rice cookies disappeared before the photographer could capture them!
6 1/2 ounces (185g) gluten-free brown rice flour (or other whole-grain, gluten-free flour)*
6 1/2 ounces (185g) gluten-free millet flour (or nut meal of choice)*
4 1/2 ounces (127g) organic granulated sugar
9 Tbsps butter (127g), softened at room temperature
1 Tbsp (15mL) rosewater (or other flavoring of choice, such as lemon extract)
1/2 tsp (2.5mL) gluten-free vanilla extract
+/- 1 Tbsp water
1/4 tsp fine sea salt
1/4 cup seedless raspberry jam
*Due to significant inherent dangers of cross-contamination in the harvesting, storing, processing, and packaging of various grains, seeds, etc. please be sure only to use certified gluten-free flours whenever preparing food for individuals with celiac disease or severe gluten sensitivity. FDA guidelines now state a product is only truly (and safely) gluten-free when it is tested by reliable methods and shown consistently to have 20ppm or fewer of gluten.
Position wire baking wrack or shelf in the center of the oven and preheat to 350 degrees Fahrenheit (170 Celcius). Line a large baking sheet with parchment paper or non-stick liner (such as Silpat) and set aside.
In the bowl of a large food processor fitted with the standard metal blade, combine millet and rice flours and salt. Turn on and run until the ingredients look well-mixed, approximately 15 seconds. Divide the butter into one-tablespoon portions, add to the mixer together with the flavorings and pulse until it starts binding with the flours. If the dough seems too dry or it is not binding well after about 20 pulses, add a tablespoon of water and pulse a few more times. Repeat with another tablespoon of water if necessary. The dough is not going to make a smooth ball. When it is just barely hanging together (in what the Times calls a "shaggy" dough, turn the processor off, unplug from the wall and grab a walnut-sized (roughly 1-1/4 inch or 3 cm across) lump of dough.
In one hand, press the small lump of dough tightly in a circular shape between thumb and forefinger while simultaneously pressing from below with the other hand to flatten the bottom. When a disc-like shape has been achieved, continue squeezing dough securely between the thumb and forefinger of one hand while using the forefinger (alas, "thumb"print is a bit of a misnomer) of the other hand to twist out a small indentation in the top center of the cookie. The cookie should now resemble a little cup with an even thickness of dough surrounding the indentation. Place the cookie on the prepared baking sheet and fill the indentation with a rounded 1/8 teaspoon (1 mL) of desired jam or other filling. Repeat process until all dough is used up, placing cookies about 3/4 inch (2 cm) apart on the sheet. They will spread slightly during baking.
Bake for 11-13 minutes or just until bottoms just begin to turn golden. Remove baking sheet from oven and place the sheet on a wire rack to cool. Do not attempt to remove cookies from the sheet until they have completely cooled (at least 15 minutes) or they will fall apart. Leave at room temperature in an airtight container for up to 3 days or freeze leftovers for up to a month. To defrost, remove frozen cookies from container and place on a platter at room temperature for 30 minutes.